This enigma became famous as it was proposed to the 8-year-old students of a Vietnamese school. And you ... Are you as smart as an 8-year-old Vietnamese boy?
The exercise consists of complete the boxes with the numbers from 1 to 9 without repeating any.
There are 362,880 possible combinations to place the 9 digits in the 9 blanks, but only a few are correct. Here we present one of the possible solutions: